Sam Bull

Sets the site locale dynamically according to visitor preference. 
This preference comes from the user’s browser.
To install all available translations click the ‘Install All’ button in Settings->General. 
To install individual locales, select the site language and save changes for each locale you want to install.
Technical details: 
 Will parse the Accept-Language HTTP header and find the best matching language for the user from the translations available on the site.

Preferred Locale

Select site locale/language according to user preference (set in their browser).

Complete Language Switcher is a plugin that allows you to setup your blog with multilingual support.
It also allows you to switch between languages with a nice list of flag which are easily styled.
Complete Language Switcher filters out the posts tagged with a certain language to displayed. Other languages will be hidden in the listings.
<pre><code>Note that this plugin requires the xili-language plugin in order to work.
</code></pre>

Complete Language Switcher

Switch between languages with ease using xili-language plugin. Displaying only the posts in the set language.

Preferred Locale vs Complete Language Switcher